The present invention relates to a magnetic head which is used for recording and playing back with a flexible recording medium such as floppy disk.
In a conventional magnetic head used for recording and playing back with a floppy disk, the magnetic head of straddle type and the magnetic head of tunnel type are used. The magnetic head of straddle type enables the width of the recording and reproducing core in the shape of I to widen, and has higher magnetic efficiency and higher output than the magnetic head of tunnel type.
FIG. 1 through FIG. 4 show one example of conventional magnetic heads of straddle type with a slider. FIG. 1 is a top plan view of a magnetic head with a slider, FIG. 2 is a cross sectional view taken on line II-II' of FIG. 1, and FIG. 3 and FIG. 4 are cross sectional views explaining a bad condition after constructing a magnetic head with a slider.
In FIG. 1 through FIG. 4, a magnetic head 1 with a slider comprises a magnetic head core and a slider 2 for slidably guiding the floppy disk by the top surface of the slider. The slider is made of nonmagnetic materials such as ceramics or the like which has an endurable characteristic against abrasion and the magnetic head core includes at least one recording and reproducing head core 3 made of magnetic materials such as ferrite.
As shown in FIG. 1, the slider 2 has a pair of erasing head cores 5 made of magnetic materials such as ferrite with an erasing gap 4, and a ditch 6, as shown in FIGS. 1 and 2. On the other hand, the recording and reproducing magnetic head core 3 has a recording and reproducing gap 7 as shown in FIG. 1.
The slider 2 and the recording and reproducing head core 3 are bonded as one body by adhering materials 8, as shown in FIGS. 1 and 2. In general, sliding surfaces 10 and 11 of the slider 2 and the recording and reproducing magnetic head core 3, which are touched with a floppy disk 9, are finished minutely by lapping.
Although the sliding surface 10 of the slider 2 and the sliding surface 11 of the recording and reproducing head core 3 are finished minutely by lapping, the conventional magnetic head 1 has a drawback that a change of temperature and humidity makes a small step 12 between the sliding surface 10 of the slider 2 and the sliding surface 11 of the recording and reproducing magnetic head core 3, as shown in FIGS. 3 and 4. For example, the step 12 is caused, when the sliding surface 11 of the recording and reproducing magnetic head core 3 thrusts out, as shown in FIG. 3, and conversely when the recording and reproducing head core 3 sinks below the sliding surface 10 of the slider 2, as shown in FIG. 4. Although the height of the step 12 is a small value which is smaller than 1 micrometer, the step 12 could have an important influence upon a function of a disk playing device.
Therefore, as shown in FIG. 3, in case the sliding surface 11 of the recording and reproducing head core 3 thrusts out above the sliding surface 10 of the slider 2, a sharp edge 13 of the recording and reproducing head core 3 damages a surface of the floppy disk 9. On the other hand, as shown in FIG. 4, in case the sliding surface 11 of the recording and reproducing head core 3 sinks below the sliding surface 10 of the slider 2, a spacing loss when recording and reproducing may be undesirably increased.